1. Field of the Invention
The present invention relates to a terminal device usable to make connections to conductors. More particularly, the present invention relates to a terminal device/connecting device for electrically connecting to at least two electrical conductors in a housing having a tubular plug, with a contact holder in the tubular connecting plug, the contact holder having contact elements passed through recesses in conductor holders to make contact with the conductors.
2. Description of the Related Technology
A terminal device already known is described in DE-195 04 013 C1 (see especially FIGS. 13-16). The subject matter of this device is mainly a reusable tap to continuous multiwire lines, preferably on two-wire profiled flat ribbon cables (ASI lines) with current-carrying flexible leads, for example for measurement purposes at different points of the ASI lines. To connect the ASI line to a branching line the latter is inserted through a connecting sleeve into the housing in which the correspondingly shaped contacts (FIG. 17) connect the wires of the ASI line to the pertinent wires of the branch line.
In particular, as a result of the different terminals of continuous and branching lines the structure of the terminal device for a connection device of this type is complex. Moreover the contact elements which are to be equipped with penetration spikes as well as with an insulation piercing connecting device are complex parts which moreover need be guided very accurately in order to enable simultaneous contact-making of the wires of ASI and branch line.
With this at least alignment assumption, secure installation and function are not guaranteed because the wires of the branch line are not reliably guided and their location can be checked when the contact carrier is being inserted when using transparent material, but can easily deviate from the desired position.
In addition, the required supports represent additional cost for support of the wires of the branch line. Furthermore, the known device is neither intended nor suitable for accommodating electrical devices such as plug-in connectors or branch connecting sleeves.
Finally, the terminal device which had been published previously is not suited for building connecting structures by joining several identical devices, but in any case for connecting two ASI lines if the branch line on the free end does not have an actuator or sensor as provided in column 6, lines 13-14 of the patent, but via another PG gland is inserted in the threaded connecting sleeve of a second terminal device as shown in FIGS. 13-16 and is electrically connected therein to an ASI line.
An object of the present invention is therefore to devise a terminal device of the initially mentioned type as simple and economical as possible, which enables reliable mechanical and electrical connection of the wires of at least two cables to be connected to contacts of plug-in connectors which are located in the threaded connecting sleeves of the terminal device and to other terminal devices.
This object is achieved by providing conductor holders in tubular threaded connecting sleeves with recesses that extend into the conductor holders to axial channels where conductors are positioned so that contact elements are guided through the recesses to contact-making sites in the axial channels where electrical connections to conductors are made.
The conductor holder of the present invention enables simple, economical and mainly stable positioning of the conductors in the terminal device for absolutely reliable contact-making with the contact elements which are inserted transversely thereto and thus enables prompt and reliable installation. To do this first of all the conductors must be inserted into the holes of the conductor holder and this unit inserted into the intended threaded connecting sleeve and then the contact elements are pressed through the recesses which run transversely to the holes. A visual inspection is unnecessary since the conductors and the contact elements are guided on all sides.
The conductors can advantageously be both conductor wires and also metal parts matched to the requirements of the respective application. Since to connect cables their end parts must be stripped to be able to insert the wires into the holes of the conductor holder, the terminal device is suitable both for round and flat cables.
Since the terminal device is intended solely for conductor connections and not for taps, the contact elements can be made simple, and when penetrating spikes are omitted, can be made both for contact-making of flexible lead and also of solid conductors.
The housing of the terminal device can also be made and produced more simply because supports or rests for conductors which are to make contact with one another are unnecessary. The uniform use of conductor holders for each connection moreover dictates a structure of the terminal device which is simpler and more economical than in the described prior art.
Furthermore, with a terminal device a larger number of connections is possible and depends on the number of threaded connecting sleeves provided. In practice this number is limited by the allowable maximum dimensions of the terminal device. A structure which is suitable for many applications has four threaded connecting sleeves. A favorable compromise being achieved between the size of the device and the number of possible connections.
One special advantage of the terminal device of the present invention lies ultimately in that it is suitable as a module for building any number of connecting structures. To do this only the terminals of at least one threaded connecting sleeve need be connected to each of several terminal devices. Together with the internal connections of each terminal device, complex connecting networks which can be optimally matched to the circumstances of each individual case can thus be built and they moreover can be modified and expanded at any time.
Advantageous embodiments of the terminal device of the present invention are described below.
The arrangement of one conductor holder per threaded connecting sleeve of the present invention very easily makes it possible to provide different arrangements for connection which can be easily joined via the conductors to be inserted into the channels of the conductor holder.
At least a cable gland, plug-in connector, or connecting piece with multiple conductor holder can be attached alternatively to the threaded connecting sleeve, by which a large diversity of possible terminal devices which thus have high utility can be achieved.
Thus, the terminal device can be made for example as a pure cable connector of three or four cables, for which in each threaded connecting sleeve there is one cable gland and the wires of each stripped cable end are placed in the pertinent conductor holder.
It is also possible to install in a threaded connecting sleeve a plug-in connector for connecting a mating connector, for example a cable set. In doing so the plug-in contact elements can be connected via individual conductors such as flexible leads, solid wires or tailor-made metal parts, but also via the conductors of cable pieces stripped on the ends or via conductors which are permanently connected to the plug-in contacts and which on the other end can be inserted into the channels of the conductor holders provided for this purpose.
Another especially feasible means consists finally in the indicated connecting piece which is simple to build and install and enables prompt joining of the terminal devices of the present invention into mechanically stable units.
Making the conductive connection of the two conductor holders of the connecting piece by use of spring-elastic sheets results in a mechanically durable connection which can be easily produced and installed by machine which moreover ensures not only a permanently reliable connection between the connected terminal devices, but also high quality contact-making with the contact elements adjoined by the metal part under spring pressure.
To do this the contact elements can be selectively made as pins or spikes which can be inserted between the sheets or as legs for example of the contacts of the insulation piercing connecting device surrounding the sheets. Also a mixed execution of the contact elements is of course possible.
Making the contact elements as insulation piercing connecting devices is especially advantageous since the reliable contact-making is thus largely independent of the type of conductor. As mentioned, insulated and uninsulated flexible leads, solid wires or other metal parts which are rigid or elastic in the contact area are equally well suited.
Especially fast and uncomplicated installation of the terminal device is achieved in that the conductor holder, regardless of the devices to be connected, are identical. This obviates not only the necessity of assignment to the different devices, but also making available and storing different conductor holders are unnecessary.
In terminal devices with two conductor holders which are not located opposite one another or for more than two conductor holders, the use of mating overlapping end parts on the conductor holder end faces offers the advantage of small dimensions of the housing due to shorter threaded connecting pieces and in addition of the cross section of the terminal plug since the contact elements can be located in a narrow space. The possibility of overlapping is dependent on the number of conductor holders and contacts per conductor holder. With reasonable cost this execution can be easily accomplished for up to four threaded connecting sleeves with two-pin terminals.
Greatly simplified installation, especially in an embodiment of the conductor holder with mating overlapping end parts, is achieved by coding for correct-angle insertion of the conductor holders into threaded connecting sleeves which allows insertion of the conductor holders into the threaded connecting sleeves in only a single position which can also be found xe2x80x9cblindxe2x80x9d.
One possible embodiment of this coding is to use flattened surfaces on the exteriors of conductor holders and on the interior surfaces of threaded connecting sleeves. For example, by having the flattened surfaces area extend only over a portion of the longitudinal length of the conductor holder has the additional advantage that a projection is formed without added costs, which can be used as a stop in the insertion of the conductor holder into the threaded connecting sleeve. Moreover the flattened areas also cause effective locking.
Funnel-shaped insertion openings of the channels enables easy insertion of the conductors.
A quite significant facilitation of installation is achieved by a clamping element which can be active in each channel. When connecting for example one cable first the cable wires can be inserted into the channels and this unit can then be inserted into the pertinent threaded connecting sleeve in any sloped position without the fear of the conductor holder sliding out of the conductor ends or without special aids being necessary to prevent this sliding out. Rather as a result of the light clamping of the cable wires the indicated unit is premounted and then can be easily inserted in the threaded connecting sleeve when this takes place from top to bottom.
A spring tongue which is produced integrally together with the conductor holder in an injection molding process for example is economical and has sufficient spring action even for relatively thick and inelastic plastic.
In practical application a shielded version of terminal devices is often necessary.
In the cable gland the conductive connection of the cable shield to the metal housing takes place via an annular metal spring which adjoins the cable shield and via a metallic thrust collar which adjoins the metal housing and which is conductively connected to the spring.
In a connected plug-in connector with an outside sleeve of conductive material this and/or a plug-in contact at ground potential is connected to the metal housing via a metal piece.
A connecting piece for this purpose has an annular metal piece on the periphery which when union nuts are screwed to the two metal threaded connecting sleeves to be joined adjoins the latter.
Feasibly these conductive connections are made such that they are also effective in a plastic-spray coated metal housing.
In another embodiment of the invention there is on the contact carrier in the threaded plug a circuit board on which not only economical conductive connection of the contact elements intended for this purpose by simple printed conductors can be effected, but in addition also the connection of electrical components, for example a terminating resistor, is easily enabled.
The threaded plug is opened for inserting, connecting and wiring of the printed boards and can be closed by means of a screw-on cover.